An on-line retailing firm conducts a study into the number of on-line purchases of footwear made during all of last year.   The study wants to determine the proportion of Australians over the age of 25 who purchase footwear on-line. The managing director of the on-line retailing firm believes this proportion of Australians is 22%. A random sample of 179 Australians over the age of 25 is selected. If the managing director’s claim is true, what is the sample proportion value below which 10% of all sample proportions would exist? Express your answer correct to two decimal places.

A group of marketing students at a large university wants to determine the proportion of first year students who use certain types of social media. The students want their estimate to be within 0.03 of the true proportion with a 95% level of confidence. Two years ago, a similar study determined the proportion to be 0.796. How large of a sample is required?

A new airline has just expanded its network to Australia and is interested in determining the proportion of its Australian customers who are flying overseas for business.  Based on its experience in other markets, the airline estimates that the population proportion is 30%. It wants its confidence level to be 98%, and the error to be within 5%. How many random customers should the airline survey?

A researcher would like to estimate p, the proportion of U.S. adults who support raising the federal minimum wage.Due to a limited budget, the researcher obtained opinions from a random sample of only 1,432 U.S. adults. With this sample size, the researcher can be 95% confident that the obtained sample proportion will differ from the true proportion (p) by no more than which of the following percentages (answers are rounded)? 0.07% 2.6% 3.0% 5.2%

A researcher would like to estimate p, the proportion of U.S. adults who support raising the federal minimum wage.If the researcher would like to be 95% sure that the obtained sample proportion would be within 2.4% of p (the proportion in the entire population of U.S. adults), what sample size should be used? 6,945 1,737 435 42

uppose that 20% of the residents in a certain state support an increase in the property tax. An opinion poll will randomly sample 400 state residents and will then compute the proportion in the sample that support a property tax increase.How likely is the resulting sample proportion to be within 0.04 of the true proportion (i.e., between 0.16 and 0.24)?(Hint: Use the sampling distribution of the sample proportion in this case.) It is certain that the resulting sample proportion will be within 0.04 of the true proportion. There is roughly a 99.7% chance that the resulting sample proportion will be within 0.04 of the true proportion. There is roughly a 95% chance that the resulting sample proportion will be within 0.04 of the true proportion. There is roughly a 68% chance that the resulting sample proportion will be within 0.04 of the true proportion.